package dmsxl.dongtaiguihua;

/**
 * Author: Zhang Dongwei
 * Date: 2023/7/26 21:38
 */
public class dtgh9_96 {

    public static void main(String[] args) {
        System.out.println(numTrees(3));
    }

//    视频答案，效果较好
    public static int numTrees(int n) {
        int[] dp = new int[n + 1];
        dp[0] = 1;
        for (int i = 1; i <= n; i++){
            for (int j = 1; j <= i; j++){
                dp[i] += dp[j-1] * dp[i-j];
            }
        }
        return dp[n];
    }
}
